Charging regulator



April 28, 1931. E. KRAMER 1,802,658

CHARGING REGULATOR iled Dec. 19, 1928 2 Sheets-Sheet 1 AP111 8, 1931. E. KRAMER l,802,'658

CHARGING REGULATOR Filed Dec. 19, 1928 2 Sheets-Sheet 2 $144M, 6411M 7M,

Patented Apr. 28, 1931 UNITED. STATES PATENT OFFICE ERWIN KRAMER, OF BERLIN, GERMANY, ASSIGNOB TO HARTSTOFF-METALL AKTIEN- v GESELLSCHAFT, OF BERLIN-COPENICK, GER-MANY CHARGING REGULATOR Application filed December 19, 1928, Serial No. 326,944, and in Germany December 23, 1927.

My invention relates to a regulator, which shall act upon the charging of mills and similar machines, or upon the feeding of the same with the material to be treated, in

dependency of the amount of electric our rent supplied to the operating motor, so that the supply is effected in a measure as to result in a uniform load of said motor within practical limits.

The regulation is obtained with the aid of an electromagnet included in the circuit of said operating motor, but instead of said electromagnet any other suitable device may be used, the action of which varies according to the strength of the current at the time being.

With the aid of my new device one obtains an accurate regulation without the opening or closing of any contacts which, especially 'in dust-laden plants, often are the cause of disturbances.

The regulating effect from the member acted on by the strength of the motor is transmitted to the charging or feeding device purely mechanically, and care .is taken that this mechanical transmission takes place without detrimental friction, retardation or load uponthe member subjected to the action of the strength of the electric current, whereby the accuracy of the operation of the device could be affected. Another advantage of the new device is this that, with its aid, one can continually so charge the mill, etc, as to practically insure a full output of the machine, while restricting the regulation to the maximum de-. livery. The consumption of energy of dis integrating ,machines, e. g. beetling mills, fluctuates because of the irregularities of the material supplied. Moreover, the feeding devices (provided, they are not designed so as to effect the feeding according to the weight of the material being fed) frequently supply unequal amounts of materialin a certain unit of time; To prevent the motor from being overloaded it is, for the reason just stated, necessary to adjust the feeding device for a smaller amount than corresponds to the performance of the machine.

As a whole, it is very diflicult to so adjust the feeding or charging device that the operating motor is about fully utilized. The new device (independenoy, of the condition of the material to be dealt with) permits the continual charging to be adjusted, for instance, to about 80% of the output of the machine, and to utilize the capacity of the machine as regards the rest in such a manner by means of the automatic regulation that the full capacity of the machine is completely utilized within practical limits without overloading.

The invention is illustrated diagrammatically and by way of example on the accompanying drawing, on which Fig. 1 is a vertical longitudinal section through a charging regulator designed according to this invention, Figs. 2, 8 and 4 show some details to be hereinafter mentioned, while Fig. 5 diagrammatically shows the operating motor in combination with the regulator.

The embodiment shown in the drawing is so designed that the continual charging is effected purely mechanically, whereas in the periods of maximum output the charging is automatically regulated.

On the drawing, 1 denotes a casing, and 2 and 3 are two horizontal shafts rotatably supported in the walls thereof. vThe driving power is transmitted to the shaft 2 by means of a Worm-wheel 4. Instead of this worm-wheel 4 any other power-transmitting member may of course be provided. The shaft 2 is provided with two cog-wheels 5 and 6 in mesh with cog-wheels 7 and 8 carried by the shaft 3. The diameters of the four cog-wheels are so chosen, that the number of revolutions of the wheel 7 is greater than the number of revolutions of the wheel 8. The latter is loosely mounted upon a sleeve 9 keyed to the shaft 3 and connected firmly with a ratchet-wheel 10 co-operating with a pawl 11 attached to the wheel 8. This wheel and the pawl are shown separately in Fig. 4. The arrow indicates the direction of rotation. The pawl 11 is retained in the teeth of the ratchet-wheel by a spring 12. If the shaft 2 is rotated in the direction indicated by the arrow 13 (Fig. 1), the shaft 3 is rotated in the direction indicated by the arrow 14 in which the pawl 11 remains continually coupled with the ratchet-wheel 10, whereby the sleeve 10 is kept coupled with the wheel 8.

The sleeve 9 is continually coupled with the member 16 of a clutch, the other mem ber 15 of which is axially movable on shaft 3 and by a pin 25 engaging a bore of the cog-wheel 7 is coupled with this wheel. In Fig. 1 the clutch member 15 is shown in gear with the clutch member 16, in consequence whereof the revolutions of the quick- 1 rotating wheel 7 are transmitted to the s eeve 9; and. therefore shaft 3 is now rotated with the same number of revolutions as wheel 7.

The clutch member 16 is provided with a cam portion 17 (Figs. 1 and 2), as well as with a lateral projection 18. The cam 17 co-operates with aroll 23 attached to the arm 20 of a bell-crank lever 20/ 21 fulcrumed at 19; the arm 21 of this lever is coupled by pivots 22 with the member 15 of the clutch, and is subjected to the pull of a tensile spring 24 continuously tending to withdraw theclutch member 15 from the clutch member 16. lVhen by means of the roll 23 the arm.20- of bell-crank lever 20, 21 has been lifted by the cam 17, the clutch members are in engagement with one another shaft. 3 rotates with the same number of' revolutions as cog-wheel- 7 When, however, the cam 17 has passed the roll 23 the spring 24 withdraws by means of the arm 21', bell-crank lever 20, 21, the clutch member' 15, in consequence whereof the quick rotation of the shaft 3 ceases. Thus, at every revolutionof the clutch member 16 the clutch me'mber15 is thrown into engage- Inent therewith for a certain length of time.

Transversely to the shafts 2 and 3' an axle 26 is mounted in the walls of the casing 1 above the shaft 3 and a vertical double-arm lever 27 is carried on said axle. The upper arm of this lever is designed as an armature for an electromagnet 28; its lower arm carries a roll 35 which co-operates with the lateral projection 18-of the clutch-member 16 against which it is'pressed by a tensile spring 32, the pulling strength of which can be adjusted or varied by a threaded pin 31, as shown As soon as projection 18 contacts with said roll: 30 and presses it to the right, the armature is moved to the left so as to approach the poles of the electremagnet 28.

The lower arm 29 of the double-arm lever also-has a projection 34 located opposite a projection 33 provided at the free end of the bell-crank lever' arm 20. The projections 33 and 34 are so arranged with respect to one another that the latter can lock the former in which case the bell-crank lever cannot be rocked by the spring 24. In the t position shown inFig. 1 the projections 33 and 34 are out of engagement because of the projection 18 of the clutch member 15 having engaged the roller 30 of the lever 27/29, as shown. If this, however, is not the case the posit-ion of the lever 27/29 is such (under the pull of the spring 32.) that the projection 34 is located below the projection 33 whereby the bell-crank lever 20/21 is prevented from withdrawing the clutch member 15 from the clutch member 16.

The length of the cam 17 and of the projection 18' is such that when the clutch is rotating, first the cam engages the roller 23, and only thereafter the projection 18 engages the roller 30. In other words: first the bell-crank lever is locked and then. the armature 27 approaches the electromagnet. If the latter is sufficiently energized it will withhold the armature 27, and the lever arm 29 with its projection 34 will remain in a position in which it is unable to lock the bell-crank lever. As the clutch then continues to rotate and the cam portion 17 of the clutch member 16 therefore, leaves the roll 20 of the bell-crank lever, the latter will yield to the pull of the spring 24, in consequence whereof the clutch member 15 will be withdrawn from the clutch member 16. Inother words: the clutch members will be disengaged and the shaft 3' now no longer rotates with the same number of revolutions asthe cog-wheel 7.

If the electromagnet 28 is, however, not sufliciently energized to retain the armature 27, the lever 27/29 will, under the pull of the spring 32, instantly resume its former position after the projection 18 of the clutch member 16 has passed the roller 30, in consequence whereof the projection 34 re-assumes its position below the projection 33 of the bell-crank lever prior to the cam ortion 17 leaving the roller 23, and, there ore, the clutch members will remain engaged.

It has already been stated that when the clutch members 15 and 16- are engaged, the shaft 3 rotates with the same number of revolutions as the cog-wheel 7 because of the coupling of the clutch member 16 with the sleeve 9 which is keyed to said shaft. But this coupling is of a particular design, in that the clutch member 16 is provided with a lug 35 (Figs. 1 and 3) while the sleeve 9 is provided with two lateral projections 3'6 and 37 located diagonally opposite to one another so that the clutch member 16 can turn for practically 180 (or less, if the parts concerned are in the position shownin Fig. without the lug 35 con tacting with one or the other of the projections 36, 37. The object of this arrangement is to prevent that every time the clutch members are engaged (also if the electromagnet keeps the armature attracted, that is to say, if the strength of the current passing through the coils of the electromagnet has already attained the required strength) simultaneously therewith the numbenof revolutions of the shaft 3 increases. When the sleeve 9' is turned in the direction indicated by the arrow 14 in Fig. 1, its projection 37 is moved towards the lug 35 of the clutch member 16, bears against it and thereby rotates the clutch member. If, on the other and the length of said parts 17 and 18, is

such that the change of the position of the levers 20/21 and 27/29 will be finished during about one-fourth of a revolution of the clutch member 16.. Throwing the clutch member 15 into, and out of, gear thus takes place, while the clutch member runs idle, provided, the electromagnet' 28 has not caused an engagement of the clutch members for a longer time.

The mechanism is preserved from undue wear and tear by the reason of the arrangement described in the preceding two paragraphs, and shaft 3 is prevented from being rotated with increased speed if a current having the prescribed strength does not flow through the electromagnet.

The feeding or charging device proper (not shown) receives the driving power by the medium of the shaft 3, for instance by means of a sprocket-wheel138 on the end' of shaft 3 and other suitable transmitting members. i

The lever 21 is preferably elastic in order to prevent fracture if, by way of chance, the claws of the clutch should encounter one another axially.

The coils of the electromagnet are inserted into the circuit in such a manner that in the case of the strength of the current in the motor becoming Weaker also the electromotor is energized to a correspondingly lesser degree, and vice versa.

The operation of the regulating device is as follows:

The shaft 2 drives the cog-wheel 8 by means of the cog-wheel 6, the revolutions of which are transmitted to the sleeve 9 by means-0f the pawl 11 and the ratchet-wheel 10, whereby also the shaft 3 is turned. The revolutions of the sleeve 9 are transmitted to the clutch member 16 by means of the projections 36 and 37 and the revolutions of the shaft 2 are transmitted also to the cogwheel 7 by means of the cog-wheel 5. The number of revolutions of the wheel 7 is considerably larger than that of the cogwheel 8 by reason of the correspondingly different diameters of the four wheels mentioned, as appears distinctly from Fig. 1.

The revolutions of the wheel 7 are transmitted to the clutch member 15 by the pin 25.

When the clutch member 16 has been rotated so far that its cam 17 engages the roll 23 of the bell-crank lever 20/21, this lever is rotated correspondingly, in consequence whereof the clutch member 15 is shifted towards the clutch member 16 until its claws engage those of its companion member 16 so that now also this latter is rotated with the high number of revolutions of the cogwheel 7. The lug is now leading, relatively to the projection 37, and assumes about the position shown in Fig. 3. In the meantime the projection 18 of the clutch member 16 has arrived opposite the roller 30 of the lever 27 /29 and has moved this lever so that its armature portion 27 has approached the poles of the electromagnet.

If the strength of the current flowing through the electromagnet is great enough the magnet will be so energized as to be able to retain the armature 27, or the lever 27/29 respectively, in the position into which it has been rocked by the projection 18 (Fig. 1), and the lever remains in this position also after said projection has left the roll 30. Thereafter also the cam 17 leaves the roll 23 so that the spring 24 moves the bellcrank lever 20/21 back into that position in which the clutch members are disengaged. In the meantime the lug 35 has moved on but has not reached the projection 36. It is obvious that the clutch member 16 has been rotated with increased speed during a certain period of time.

If the current passing through the electromagnet 28 has not the prescribed strength, the armature 27 will be withdrawn by the spring 32 as soon as the projection 18 has left the roll 30. Simultaneously therewith the projection 34 of the lever arm 29 moves forward below the projection of the bellcrank lever arm 20 whereby the spring 2 1 is prevented from moving the bell-crank lever back into its former position, in consequence whereof the clutch members 15 and 16 remain coupled with one another. This is, also, the case after the cam 17 has left the roll 23. But now the lug 35 comes up with the projection 36 on sleeve 9 and acts driving on it whereby the sleeve 9 and the shaft 3 together with its transmitting member, i. e. sprocket-wheel 38 is rotated with the same speed as the cog-wheel 7, so that also the charging device (not shown, as already stated) is actuated with correspondingly increased speed. While the clutch continues to rotate, the cam 17 arrives again under the roll 23 whereby the clutch members are kept in engagement with one another also if in the neXt moment the lever 27/29 should be turned by the action of the projection 18 upon the roll 30 so that then the projection 33 of the bell-crank lever is no longer locked by the projection 34 of the lever arm 29.

If the increased amount of charging has not been sufiicient to increase the strength of the electric current in the motor and thus, in the coils of the electromagnet also, the electromagnet is not able to keep the armature 27 attracted and the latter will be withdrawn by the spring 32 as soon as the projection 18 has left the roll 30. As the bell'crank lever is now again locked by the projection 34, it keeps the clutch members again in engagement with one another.

This operation is repeated over and over again, until the electromagnet can keep the armature again attracted. In that case the clutch member 15 will be again instantly disengaged from its companion clutch member 16 after the cam 17 has left the roll 23, as has already been described. The clutch member 16 which is braked to a certain extent by the rolls 23 and 30 comes to a standstill and remains so until the projection 37 has again come up with the lug 35 whereafter sald clutch member is again rotated,

its numberof revolutions being the same as that of the wheel 8.

Thus, at every rotation of the clutch member 16 the armature 27 is moved towards the electromagnet, but as long as the strength of the current is not that prescribed the clutch members remain engaged so that the transmission member i. e. sprock et wheel 38 is rotated continually with the increased speed until the operating motor is again running with full load. On the other hand, if the strength of the current is that prescribed, the engaging and disengaging of the clutch members takes place while the member 16 thereof runs idle in which case the number of rotations of the shaft 3 is not increased.

The height of the cam 17 is such that it is able to lift the projection 33 a little above the projection 34. Therefore, the lever 27/29, after it is no longer subjected to the action of the projection 18, has some free play, without any mechanical impediment, and is subjected solely to the tensile force of the spring 32, provided, its supporting axle be possibly free from friction, as'can be attained by supporting said axle in ball hearings or between centres, and the like. It is, thus, possible to adjust or tune the magnet and the spring 32 with respect to one another sufficiently accurately so that other influences cannot act in a disturbing or detrimental degree.

It is well known that the magnetic tensile force varies strongly even at a slight variation of the width of the gap between the pole faces and the armature, and it is, therefore, important that the armature in that moment in which a trial is made as to whether or not the current has the proper strength be just in the proper distance from the poles. This is, in the example shown, insured by the feature that the projection 18 turns the lever 27/29, or the armature 27 respectively, always into accurately the same position. It is suited to the purpose of the electromagnet and its armature to provide for a narrow gap between the poles and the armature in order to prevent the latter from sticking to the poles. This can be attained also by providing a suitably arranged abutment member for the armature.

The accuracy of the regulation by the means therefor provided depends on how often the armature is moved towards the electromagnet in the predetermined unit of time, and is, therefore, possible to increase the sensitiveness by choosing a suitable number of revolutions.

It is well-known that an electromagnet, the poles of which have no more been able to keep the armature attracted because of the strength of the current having become too small can attract the armature again only if the strength of the current has been very materially increased,'for instance by 100% and even more, and if the air gap'between the pole faces and the armature has become unusually large the electromagnet is not able to attract the armature again even if the strength of the current is nearly excessively increased. Therefore, devices designed for the purpose of enabling an electromagnet to let loose its armature if the strength of the current falls within a certain limit, and to attract it again when the strength of the current has suitably risen are of no use for the present regulating device in that it would be necessary to permit very considerable fluctuations in the strength of the electric current. The arrangement and combination of parts just described, therefore, are such that the armature when being remote from the pole faces is moved back mechanically into its former position so that the width of the gap is always the same and it is sot0say left to the electromagnet whether or not it will attract the armature. One is, thus, in the position to effect, with the device in question, a

very accurate regulation suited to all partical conditions.

The regulator as herein described and shown in the drawing by way of example permits to regulate the maximum performance at a continually uniform drive. It is, of course, also possible to design the regulator in such a manner that the uniform drive of the charging device is dispened with and a regulation is effected only if the strength has fallen below a predetermined limit.

' That can be effected by the cog-wheels 6 and 8 being omitted, and the clutch members 16 being firmly connected with the shaft 3, in which case the cam 17 and the projection 18 will then be provided on a continually rotating disk, for instance the clutch member 15 or any other disk arranged on the shaft 2 in a manner suited to the purpose in view.

I wish it to be understood that I do not limit myself to the details of the embodiment shown in the drawing. There may be variations in the details without departing from the idea of invention. Thus, for instance, rocking shafts or reciprocating levers or equivalent other members may be used instead of the rotating shafts.

In Fig. 5, the electric operating motor is shown at M, whereas the regulator is shown at R. Current is supplied to the motor M from the lines 39, 40, the current flowing from line 39 through the windings of the electromagnet 28 of the regulator, from there to the motor M and then back to line 40. The electromagnet 28, therefore, is energized in correspondence with the strength of the current passing through the motor. At K is shown a coupling, by means of which the motor can impart power to some machine.

I claim:

1. In electrically operated machines, in combination with the electric operating motor, a regulating device, comprising a rotatable shaft adapted to be driven at high speed, a second rotatable shaft adapted to transmit power to said machine, means for transmitting rotation from said first shaft to said second shaft so as to normally rotate it at a speed below that of said first shaft,

'means including a clutch adapted to temporarily impart greater speed to said second shaft, an electromagnet included in the circuit of said electric motor and adapted to be energized in correspondence with variations in the strength of the motor current, an armature for said electromagnet, means tending to draw said armature away from said electromagnet, and means controlled by said second shaft so as to move said armature toward said electromagnet, in predetermined time intervals, for the purpose described.

2; In electrically operated machines, in combination with the electric operating motor, a regulator, comprising a rotatable shaft adapted to be driven at high speed, a second rotatable shaft adapted to transmit power to said machine, means for transmitting rotation from said first shaft to said second shaft so as to normally rotate it at a speed below that of said first shaft, means on said second shaft including a clutch adapted to temporarily impart greater speed to said second shaft,an electromagnet included in the circuit of'said electric motor and adapted to be energized in correspondence with variations in the strength of'the motor current, a double-arm lever having one arm acting as an armature for said electromagnet, means tending to withdraw said. armature, means adapted to be actuated by a cam on one member of said clutch toca'use the clutch members to become engaged and means on said clutch member to move said armature, in predetermined time intervals, toward said electromagnet, for the purpose described.

. 3. In electrically operated machines in combination with the electric operating motor, a regulator, comprising a rotatable shaft adapted to be driven at high speed, a second rotatable shaft adapted to transmit power to said machine, means for transmitting rotation from said first shaft to said second shaft so as to normally rotate it at a speed below that of said first shaft, means on said second shaft including a clutch adapted to temporarily impart greater speed to said second shaft, an electromagnet included in the circuit of said electric motor and adapted to be energized in correspondence with variations in the strength of the motor current, a double-arm lever having one arm acting as an armature for said electromagnet, means tending to withdraw said armature, a bell-crank lever having one arm operatively connected with the axially movable member of said clutch and its other arm in the path of a cam on the other memberof said clutch so as to be actuated by saidcam, means on said last mentioned clutch member adapted to 'move, in predetermined time' intervals, said' armature toward said electromagnet, and means on said double-arm lever and said-bell-crank lever for'locking the latter in operative position for the purpose described.

4. The combination as specified in claim 1, in which the means for transmitting rotation from said first to said second shaft comprises two cog-wheels secured to said first shaft and two cog-wheels rotatably mounted on said second shaft in mesh with the first mentioned cog-wheels, said cogwheels having diameters to permit rotation of said second shaft by said first shaft at two different speeds, and means for coupling one or the other cog-wheel on the second shaft with this shaft.

5. The combination as specified in claim 1, in which the means for transmitting rotation from said first to said second shaft comprises two cog-wheels secured to said first shaft and two cog-wheels rotatably mounted on said second shaft in mesh with the first mentioned cog-wheels, said cog-wheels having diameters to permit rotation of said second shaft by said first shaft at two different speeds, and means for coupling one or the other co -wheels on the second shaft with this sha t, said means including a sleeve intermediate one of said cog-wheels and said second shaft, a ratchet-wheel secured to said sleeve, and a pawl on said cog- ,wheel so as to engage said ratchet wheel.

6. In electrically operated machines, in combination with the electric operating motor, a regulator comprising a rotatable shaft adapted to be driven at high speed, a second rotatable shaft adapted to transmit power to said machine, two cog-wheels secured to said first shaft, two cog-wheels rotatably mounted on said second shaft in mesh with the first mentioned wheels, said wheels having different diameters permitting said second shaft to be rotated at two different speeds, means for coupling one or the other cog-wheel on said second shaft with this shaft including a sleeve intermediate one of said cog-wheels on said second shaft and this shaft, a ratchet wheel secured to said sleeve and a pawl mounted on said cog-wheel engaging said ratchet-wheel, a movable clutch member, a second clutch member on said second shaft adapted to be coupled with said sleeve with an angular play of a greater angle than that described during the positive engagement of said clutch members, means for displacing said movable clutch member relative to said other clutch member, an electromagnet energized in correspondence with the variations in the strength of the motor current, an armature for said electromagnet, means tending to withdraw said armature and means operable by said other clutch member so as to move said armature, in predetermined time intervals, toward said electromagnet for the purpose described.

I In testimony whereof I aflix my signature.

ERWIN KRAMER. 

